CN114391251B

CN114391251B - Beam modulating apparatus and projection system

Info

Publication number: CN114391251B
Application number: CN202080056115.6A
Authority: CN
Inventors: 张金旺; 曹腾; 林威志; 王先炉; 刘志刚
Original assignee: Beijing Asu Tech Co ltd
Current assignee: Beijing Asu Tech Co ltd
Priority date: 2019-06-06
Filing date: 2020-06-05
Publication date: 2023-05-19
Anticipated expiration: 2040-06-05
Also published as: EP3981144A1; US20220236633A1; CN110312113A; CN114391251A; WO2020244621A1; EP3981144A4; US20240085774A1; CN110312113B; US11860526B2

Abstract

A beam modulating device for modulating an input light field and a projection system comprising the device are provided. The input light field has a first light field and a second light field whose polarization states differ by 90 °. The apparatus includes a PBS prism, a first LCOS panel, and a second LCOS panel. The first and second LCOS panels are over side surfaces of the PBS prism opposite the optical entrance and exit surfaces, respectively. Each LCOS panel includes a plurality of pixels on its reflective surface, wherein each pixel is controllably turned on or off such that the polarization state of a light beam reflected by a portion of the reflective surface corresponding to the light beam changes or remains unchanged. The beam modulation device can be used in projection systems, such as laser television projection systems.

Description

Beam modulating apparatus and projection system

Cross Reference to Related Applications

The present application claims priority from chinese patent application No.201910491333.1 filed on 6 months 6 2019, the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to the field of laser display technology, and more particularly to a beam modulation apparatus and a projection system.

Background

Laser television projection systems are widely used in our lives to control a projection light source using a light valve to produce a projected image, and then to magnify the projected image for display on a projection screen using a projection lens. Currently, most existing laser television projection systems include either a single-piece light valve or a three-piece light valve. Reference herein to a single-panel light valve refers to a panel of light valves that are used to load RGB (red green blue) signals in a time-division manner. The three-piece light valve referred to herein refers to three-piece light valves for loading RGB signals, respectively.

Currently, in systems employing a monolithic light valve, a monochromatic pure laser light source is typically used to excite an RGB or RGBY (red green blue yellow) fluorescent wheel. Defects such as low display luminance and low picture quality are observed due to the influence of time division. Also due to limitations in the extended invariance of the light source and light valve, in order to increase the display brightness, the size of the light valve needs to be increased, which results in a larger object surface of the UST (ultra short focal, ultra Short Throw) projection lens. Therefore, if the lens size becomes large, the body size of the entire system becomes correspondingly large. In a system using a three-color pure laser light source, the price of the green and red semiconductor laser diodes is limited, the overall cost is quite high, and the problem of laser speckle effect exists. Although the laser television projection system of the three-sheet type light valve has advantages such as high brightness and high picture quality, the lens elements used are excessive due to factors such as spectral folding of the relay light path, resulting in an elongation of the rear intercept of the UST projection lens. Under the same aperture condition, the size of the UST projection lens is also increased.

There is currently no compact, low cost, high brightness laser television projection system.

Disclosure of Invention

In view of the disadvantages associated with existing laser television projection systems, the present disclosure provides a beam modulating apparatus and a projection system.

In one aspect, the present disclosure provides a beam modulating apparatus for modulating an input light field into the beam modulating apparatus along a first axis to obtain an output light field exiting therefrom along a second axis orthogonal to the first axis. The input light field comprises a first light field and a second light field having an S-polarization state and a P-polarization state, respectively, or having a P-polarization state and an S-polarization state, respectively.

The beam modulating device includes a Polarizing Beam Splitter (PBS) prism and a Liquid Crystal On Silicon (LCOS) assembly. The PBS prisms include two right angle prisms attached to each other on their respective base surfaces and arranged such that the first and second axes are each substantially 45 ° to the interface therebetween. The PBS prism has an optical entrance surface that allows an input light field to enter therethrough and an optical exit surface that allows an output light field to exit therefrom, and an interface of the PBS prism is configured to selectively allow P-polarized incident light to be transmitted therethrough, with S-polarized incident light being reflected by the interface. The LCOS assembly includes a first LCOS panel and a second LCOS panel. The first LCOS panel is aligned over a first side surface of the PBS prism opposite the optical incidence surface such that light incident on the first LCOS panel is reflected back to the PBS prism along a first axis. The second LCOS panel is aligned over a second side surface of the PBS prism opposite the optical exit surface such that light incident on the second LCOS panel is reflected back to the PBS prism along a second axis. Each of the first and second LCOS panels includes a plurality of pixels on a reflective surface thereof, wherein each of the plurality of pixels is configured to controllably turn on or off such that a polarization state of a light beam reflected by a portion of the reflective surface corresponding to the light beam is changed or remains unchanged.

Alternatively, the input light field is a white light field optically coupled by three primary colors (i.e., the three primary colors of light together form a complex/coupling Bai Guangchang). The first light field comprises two primary color lights coupled to each other in a time-shared manner, and the second light field comprises the last primary color light. The PBS prism also includes a polarizing device, which can be a polarizing beamsplitter or a wire grid, sandwiched between the base surfaces of the two right angle prisms. The beam modulating device can further comprise one or two 1/4 wave plates sandwiched between the PBS prism and the first LCOS panel and/or between the PBS prism and the second LCOS panel. In the beam modulation device, the extinction ratio of the transmitted beam of the PBS prism is at least 500: 1. more preferably at least 1000:1. each of the two right angle prisms can include an optical glass (such as N-SF1, H-ZF3, or H-ZEAF). In the light beam modulation device, at least one of an optical incident surface, an optical exit surface, a first side surface, or a second side surface of the PBS prism is coated with an anti-reflection film for reducing fresnel reflection thereon.

In another aspect, the present disclosure also provides a projection system comprising a beam modulating apparatus according to any one of the embodiments described above.

In a projection system, the input light field can be a white light field optically coupled by three primary colors, the first light field comprising two of the three primary colors of light coupled to each other in a time-shared manner, and the second light field comprising the last of the three primary colors of light.

The projection system can further include a polarization modulation device configured to modulate a polarization state of one of the third and fourth light fields but not the other upon receiving the third and fourth light fields having substantially the same polarization state to output the first and second light fields, respectively. Alternatively, the polarization modulation device can rotate the linear polarization axis of one of the third light field and the fourth light field by 90 °. As such, the polarization modulation device can be a faraday rotator, a birefringent rotator (e.g., a half wave plate), or a prismatic rotator.

The projection system can further include a polarizing device configured to polarize the unpolarized fifth light field and the unpolarized sixth light field incident therein to output a third light field and a fourth light field, respectively. The polarizing device can include a PCS polarizing array of a front fly-eye lens configured to optically split each of the fifth and sixth light fields into a plurality of light beams, a rear fly-eye lens configured to focus the plurality of light beams on a rear surface thereof, and a prism configured to polarize the focused plurality of light beams to obtain the third and fourth light fields.

The projection system can also include a light source device configured to provide a fifth light field and a sixth light field. Alternatively, the fifth light field and the sixth light field can be configured to together form a white light field, the fifth light field being a time-division coupled light field comprising the first and second primary light (i.e. the first and second primary light being time-division coupled to form the fifth light field), the sixth light field comprising the third primary light.

Alternatively, the first primary color light is blue light, the second primary color light and the third primary color light are green light and red light, respectively, or red light and green light, respectively. In the projection system, the light source device can be configured to emit first primary color light, and can also be configured to obtain each of the second primary color light and the third primary color light by excitation of the respective fluorescent materials by the first primary color light. Alternatively, the light source device can be configured to emit the first and second primary color light, and further configured to obtain the third primary color light by excitation of the respective fluorescent material by the first or second primary color light.

The light source apparatus can include a light source module (e.g., a laser module) and two fluorescent sheets including a first fluorescent sheet and a second fluorescent sheet. The light source module comprises a first light source sub-module and a second light source sub-module, and the light source sub-modules are configured to emit a first beam of first primary color light and a second beam of first primary color light respectively. The first and second phosphor plates are optically aligned with the first and second beams of first primary light, respectively, and are configured to receive the first and second beams of first primary light. The first fluorescent sheet includes a transmissive region and a first fluorescent region on a surface thereof facing the first beam of the first primary color light. The first fluorescent region comprises a first fluorescent material (i.e. a first dye) capable of generating light of a second primary color when excited by the light of the first primary color. The first fluorescent sheet is further configured such that the transmissive region and the first fluorescent region alternately face (i.e., are aligned so as to receive) the first beam of first primary light in a predetermined manner (i.e., alternate in a predetermined temporal pattern (such as 50ms for the transmissive region and 150ms for the first fluorescent region) such that the first beam of first primary light transmitted through the transmissive region and the beam of second primary light generated by and from the first fluorescent region are coupled in a time-sharing manner to be output as a fifth light field. The second phosphor plate comprises a second phosphor region comprising a second phosphor material (second dye) on its surface facing (i.e. aligned with) the second beam of first primary color light, the second phosphor material being configured such that, upon excitation by the second beam of first primary color light, a beam of third primary color light is generated by and from the second phosphor region for output as a sixth light field.

Here, the first fluorescent sheet can be in the form of a rotating wheel (i.e., a rotating color wheel), and each of the transmissive region and the first fluorescent region is disposed in a sector region on the rotating wheel. The angles of the transmissive region and the first fluorescent region can be complementary (i.e., 360 total) and are about 89 deg. -91 deg. and about 269 deg. -217 deg., respectively. The rotating wheel can have a rotational speed of at least 7200 rpm. The second fluorescent sheet can also be in the form of a rotating wheel.

Optionally, the light source device further comprises a set of reflectors arranged such that the optical path of the first beam of first primary light transmitted through the transmission region is redirected to optically combine with the optical path of the second beam of primary light to produce the fifth light field.

In the light source module, each of the first and second light source sub-modules can include a laser diode array, and the light source module can further include first and second collimating lens arrays disposed over the light emitting surfaces of the first and second light source sub-modules, respectively. The sub-eyes in each of the first and second collimating lens arrays are arranged to be correspondingly low aligned with the laser diodes in the laser diode arrays of the corresponding light source sub-modules. Each sub-eye can include a hyperbolic aspherical lens whose curved surface is expressed as:

Wherein C is _x Is the curvature of the hyperbolic aspherical lens in the x direction, C _y Is the curvature of the hyperbolic aspherical lens in the y direction, K _x Is the cone coefficient K of the hyperbolic aspherical lens in the x direction _y Is the conic coefficient of the hyperbolic aspherical lens in the y direction.

The light source device can further include first and second dichroic filters disposed over the light emitting surfaces of the first and second light source sub-modules, respectively, and configured to filter each of the first and second beams of primary light, respectively. The far field of the first primary light can be gaussian distributed and the projection system further comprises a first diffuser and a second diffuser disposed between the first light source sub-module and the first dichroic filter and between the second light source sub-module and the second dichroic filter, respectively. The first and second diffusion sheets are configured to diffuse the first and second beams of first primary light such that their far fields are spread to have a bi-directional flat-top-like profile. Each of the first diffusion sheet and the second diffusion sheet can be configured to have a dichroic diffusion characteristic, and to have a diffusion half angle of about 1.2 ° to 1.8 °, preferably 1.5 °, in the horizontal direction, and to have a diffusion half angle of about 0.65 ° to 1.05 °, preferably 0.85 °, in the pitch direction.

The light source device can further comprise at least one means for eliminating speckle of the light field formed by the first primary light, the at least one means comprising: (1) a transmissive region comprising a fan-shaped diffuser; (2) A collimating lens module disposed over the light emitting surface of the first fluorescent sheet; (3) A collimation compensating lens and a third diffusion sheet disposed on an optical path of the first beam of the first primary color light, wherein the third diffusion sheet is configured to have a continuous small-amplitude movement. Here, the third diffusion sheet may be mechanically coupled (or connected) with a vibration motor configured to have a vibration frequency of 100Hz to 300Hz, and a diffusion half angle of the third diffusion sheet may be 2 ° to 3 °.

The light source apparatus can further include a first condensing lens module and a second condensing lens module disposed between the first dichroic filter and the first fluorescent sheet and between the second dichroic filter and the second fluorescent sheet, respectively. Each of the first and second condenser lens modules includes first and second condenser lens sub-modules including an aspherical lens and a spherical lens, respectively, in a light transmission direction. Here, the aspherical surface of the aspherical lens is expressed as:

Wherein c is the curvature at the spherical vertex, k is the quadratic aspheric coefficient, A _n And taking 2-7 as the aspherical coefficient of the higher-order term, wherein ρ is the normalized radial coordinate.

In the projection system, the light source device can optionally be configured to emit third primary color light, and can also be configured to obtain each of the first primary color light and the second primary color light by excitation of the respective fluorescent materials by the third primary color light. The light source apparatus can include a light source module and a third fluorescent sheet. The light source module can include a third light source sub-module and a fourth light source sub-module configured to emit a first beam of third primary color light and a second beam of third primary color light, respectively. The third phosphor sheet is optically aligned with the first beam of third primary color light and includes a third phosphor region and a fourth phosphor region on a surface of the third phosphor sheet facing the first beam of third primary color light. The third fluorescent region comprises a third fluorescent material capable of generating light of the first primary color when excited by light of the third primary color. The fourth fluorescent region comprises a fourth fluorescent material capable of generating light of the second primary color when excited by light of the third primary color. The third phosphor sheet is further configured such that the third phosphor region and the fourth phosphor region alternately face the first beam of third primary color light in a predetermined manner such that the light beam of the first primary color light generated on the third phosphor region and the light beam of the second primary color generated on the fourth phosphor region are coupled in a time-sharing manner to be output as a fifth light field. The second beam of third primary light is output as a sixth light field. Here, in one example, the first primary color light and the second primary color light can be green light and red light, respectively, or can be red light and green light, respectively, and the third primary color light can be blue light.

Throughout this disclosure, the terms "module," "unit," and the like refer to a particular optical device or assembly of optical components or devices that perform a particular function.

Throughout this disclosure, the relative terms "about," "left-right," and the like, following a number refer to a description of the actual number within 5% of the indicated number. In one illustrative example, "about 1.00" can be interpreted as an actual number of 0.95 to 1.05.

Drawings

FIGS. 1A and 1B illustrate block and block diagrams, respectively, of a beam modulating device provided by some embodiments of the present disclosure;

FIGS. 2A and 2B illustrate the optical path within the beam modulating device when a P-polarized light beam enters the PBS prism of the beam modulating device with the pixels on the first LCOS panel in an "on" state (FIG. 2A) and an "off" state (FIG. 2B), respectively;

FIGS. 2C and 2D illustrate the optical path within the beam modulating device when the S-polarized light beam enters the PBS prism of the beam modulating device with the pixels on the second LCOS panel in the "on" state (FIG. 2C) and "off" state (FIG. 2D), respectively;

FIG. 3 illustrates a block diagram of a projection system according to some embodiments of the present disclosure;

Fig. 4A and 4B show the optical paths and schemes in a light source device according to two different embodiments of the present disclosure, respectively;

FIG. 5 shows a front view of a schematic structure of a laser television projection system according to one particular embodiment of the present disclosure;

FIG. 6 illustrates a bottom view of the laser television projection system of FIG. 5;

FIG. 7 illustrates a right side view of a partial structure in an embodiment of the laser television projection system of FIGS. 5 and 6;

FIG. 8 shows a block diagram of a PCS polarizing array prism in an embodiment of a laser television projection system; and

fig. 9 shows a block diagram of a projection light source in an embodiment of a laser television projection system.

Detailed Description

The technical solutions provided in the various embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings of the present disclosure. It should be noted that the embodiments provided by the present disclosure should be considered as representing only a part of, but not all, the embodiments covered by the present disclosure, and thus should not be considered as imposing any limitation on the scope of the present disclosure. Other embodiments that vary somewhat in design, based on the embodiments provided herein, so long as they follow the inventive subject matter disclosed herein and are readily available to those of ordinary skill in the art without the benefit of the inventive faculty, are intended to be encompassed within the scope of this disclosure.

In a first aspect, the present disclosure provides a beam modulating device configured to modulate and/or redirect an input light field into it, resulting in an output light field.

Fig. 1A illustrates a block diagram of a beam modulation device provided by some embodiments of the present disclosure. As shown, beam-modulating device 1000 includes PBS prism 100 and Liquid Crystal On Silicon (LCOS) assembly 200 optically coupled to each other to modulate an input light field prior to outputting an output light field. The input light field is configured as a composite light field comprising two spatially coupled light fields (i.e., a first light field and a second light field), both of which are linearly polarized light beams but have two different orthogonal linear polarization states (i.e., an S-polarization state and a P-polarization state). In other words, among the input light fields configured to enter the light beam modulation device 1000, the first light field and the second light field are configured as a P-polarized light beam and an S-polarized light beam (as shown in fig. 1A) or as an S-polarized light beam and a P-polarized light beam (not shown in the figure), respectively.

Optionally herein, the input light field is also configured as a white light field optically coupled by the three primary colors. In particular, the first light field can comprise two primary colors of light (e.g. a first primary color light and a second primary color light) coupled to each other in a time-shared manner, while the second light field comprises the last primary color light (i.e. a third primary color light). This configuration of the input light field allows the beam modulation device 1000 to be used as part of a projection system, such as a television projection system or a micro-display system (e.g., virtual Reality (VR), augmented Reality (AR) display, etc.), to project/display color images based on the output light field emitted thereby.

Optionally, beam-modulating device 1000 can further include a 1/4 wave plate assembly 300 (shown in dashed box in FIG. 1A), which is optically coupled to both PBS prism 100 and LCOS assembly 200, and is configured to increase the contrast of the output light field emitted from beam-modulating device 1000.

The block diagram of the beam modulating apparatus 1000 shown in fig. 1A is further shown in fig. 1B. As shown, in apparatus 1000, PBS prism 100 includes two right angle prisms (i.e., triangular prisms) 120 and 140 that are attached relative to each other on their respective bases (i.e., hypotenuses) to form a PBS cube. Alternatively, the two

prisms

120 and 140 are glued or bonded together by providing a thin film of optical cement and/or adhesive material (e.g., epoxy) at the interface C between the two

prisms

120 and 140. Alternatively, the two

prisms

120 and 140 can be placed together without the use of glue and/or adhesive.

PBS prism 100 has an optical entrance surface a and an optical exit surface B, with an input light field configured to enter PBS prism 100 along a first axis through optical entrance surface a, and an output light field configured to exit PBS prism 100 along a second axis orthogonal to (i.e., substantially 90 °) the first axis through optical exit surface B. The first axis and the second axis are both substantially 45 ° with respect to the interface C.

Interface C of PBS prism 100 is configured to selectively allow P-polarized incident light to be transmitted therethrough and S-polarized incident light to be reflected. For this purpose, polarizing device 130 can be sandwiched at interface C to make it a polarizing surface of PBS prism 100. Alternatively, the polarizing means 130 can comprise a polarizing beam splitting film or a wire grid. In one example, the polarizing beamsplitter can include a dielectric beamsplitter coating that can be applied to the hypotenuse surface of one or both of the

triangular prisms

120 and 140, which would then be optically tackyThe binder is bonded together. Depending on the application, the PBS prism can be configured to have different extinction ratios (T _P ：T _S ). For example, in applications such as television projection systems or VR/AR display systems, PBS prism 100 in beam modulating apparatus 1000 can have a value of at least 500:1, or more preferably, has an extinction ratio of at least 1000: extinction ratio of 1.

As shown in fig. 1B, the LCOS assembly 200 includes two LCOS panels. First LCOS panel 220 is disposed over a first side surface of PBS prism 100 opposite optical entrance surface a, and is configured such that its reflective surface D2 faces PBS prism 100 and is parallel to the first side surface, such that an incident light beam from PBS prism 100 can be reflected back to PBS prism 100 along a first axis. The second LCOS panel 240 is disposed above a second side surface of the PBS prism opposite the optical exit surface B, and is configured such that its reflective surface D4 faces the PBS prism 100 and is parallel to the first side surface, such that an incident light beam from the PBS prism 100 can be reflected back to the PBS prism 100 along a second axis.

Each of the first and

second LCOS panels

220, 240 includes a plurality of pixels on its respective reflective surface, wherein each of the plurality of pixels is configured to controllably turn on or off such that the polarization state of the light beam reflected by the portion of the reflective surface corresponding to the light beam changes or remains unchanged.

Fig. 2A and 2B illustrate the optical path of a P-polarized light beam within the input light field ("P-polarized (input)") when the pixel is in an "on" state (solid circle in fig. 2A) or an "off" state (open circle), the light beam enters PBS prism 100 through optical entrance surface a, is transmitted through polarizing interface C, and strikes first LCOS panel 220 at an area corresponding to a particular pixel thereon, wherein the arrowed straight line and arrowed dashed line refer to the P-polarized light beam and S-polarized light beam, respectively. As shown in fig. 2A, if the pixel is on, an incident P-polarized light beam ("P-polarized (incident)") is reflected back to produce a reflected S-polarized light beam ("S-polarized (reflected)") that enters PBS prism 100 and is reflected by it when reaching polarizing interface C, exiting PBS prism 100 through optical exit surface B for output. As shown in fig. 2B, if the pixel is off, the incident P-polarized light beam ("P-polarized (incident)") is reflected back by first LCOS panel 220 to produce a reflected P-polarized light beam ("P-polarized (reflected)") that enters PBS prism 100 and is transmitted through polarized interface C upon reaching that interface to exit PBS prism 100 through optical entrance surface a, and is lost without output from optical exit surface B. Thus, by controlling the state of the pixels on first LCOS panel 220, the input P-polarized light beam can be manipulated to be output (as an S-polarized light beam) from optical exit surface B of PBS prism 100 or lost.

Fig. 2C and 2D show the optical path of an S-polarized light beam within the input light field ("S-polarized (input)") when the pixel is in either the "on" state (solid circle in fig. 2C) or the "off" state (open circle in fig. 2D), the light beam enters PBS prism 100 through optical entrance surface a, reflects at polarizing interface C, and strikes second LCOS panel 240 at an area corresponding to a particular pixel thereon, wherein the arrowed straight line and arrowed dashed line refer to the P-polarized light beam and the S-polarized light beam, respectively. As shown in fig. 2C, if the pixel is on, the incident S-polarized light beam ("S-polarized (incident)") is reflected back through the second LCOS panel 240 to produce a reflected P-polarized light beam ("P-polarized (reflected)") that enters PBS prism 100 and is transmitted through polarized interface C upon reaching the interface to exit PBS prism 100 through optical exit surface B for output. As shown in fig. 2D, if the pixel is off, the incident S-polarized light beam ("S-polarized (incident)") is reflected back through the second LCOS panel 240 to produce a reflected S-polarized light beam ("S-polarized (reflected)") that enters PBS prism 100 and is reflected again upon reaching polarizing interface C to exit PBS prism 100 through optical entrance surface a, and is lost without output from optical exit surface B. In this way, by controlling the state of the pixels on the second LCOS panel 240, the input S-polarized light beam can be manipulated to be output from the optical exit surface B (as a P-polarized light beam) or lost.

It should be noted that fig. 2A and 2B and fig. 2C and 2D show only two extreme states (i.e., "on" and "off") of the pixels on the first LCOS panel 220 and the second LCOS panel 240, respectively. For pixels on a particular LCOS panel, it can be manipulated to allow partial polarity (or polarization state) conversion (i.e., polarization rotation at an angle of 0 ° < a <90 °) of the incident light beam, so that the reflected light beam is essentially a mixture of P-polarized and S-polarized light beams. Depending on the source of the reflected light beam, only the corresponding light beam can achieve an output from the optical exit surface B of the PBS prism 100, which is only a part of the light beam, not the whole.

It should also be noted that the above two pixel control operations for the input P-polarized and S-polarized light beams in the input light field can be performed simultaneously in synchronization to achieve controlled spatial coupling of the two output light beams to produce color pixels of different pitches on the display screen.

It should also be noted that each of the first and

second LCOS panels

220, 240 contains a plurality of pixels (i.e., a plurality of first pixels and a plurality of second pixels) whose states can be individually controlled by means of a control circuit (not shown), such as a CMOS chip or another chip, which is assembled with the LCOS panel and configured to receive instructions from the processor based on a predetermined program. In this way, a color image can be generated on a display screen based on an output light field output from the beam modulation device disclosed herein, which is substantially a combination of a plurality of output light beams corresponding to a plurality of first pixels and a plurality of second pixels on a first LCOS panel and a second LCOS panel, respectively.

As further shown in fig. 1B, a 1/4 wave plate assembly 300 comprising two 1/4 wave plates (i.e., a first 1/4 wave plate 320 and a second 1/4 wave plate 340) can be provided in the beam modulating device 1000. The first 1/4 wave plate 320 is sandwiched between the PBS prism 100 and the first LCOS panel 220 along a first axis, and the second 1/4 wave plate 340 is sandwiched between the PBS prism 100 and the second LCOS panel 240 along a second axis. It should be noted that the two 1/4 wave plates are optional and that only one of the two 1/4 wave plates may not be provided or may be provided in the beam modulating device 1000.

In beam-modulating device 1000, an anti-reflective or anti-glare (AR) coating or film can be selectively disposed on one or more of optical entrance surface a, optical exit surface B, first side surface, or second side surface of PBS prism 100 in order to reduce fresnel reflection on these surfaces.

In a second aspect, there is also provided a projection system comprising a beam modulating device as described above.

Fig. 3 illustrates a block diagram of a projection system according to some embodiments of the present disclosure. As shown, the projection system 001 includes a light source device 4000, a polarization device 3000, a polarization modulation device 2000, a beam modulation device 1000, and a projection device 5000, which are optically coupled in order in the optical path.

Wherein the beam modulating device 1000 can be based on any of the embodiments of the beam modulating device described in the first aspect above. According to the above-described configuration, the beam modulation device 1000 is configured to modulate an input light field comprising a first light field and a second light field having different linear polarization states (i.e., S-polarization and P-polarization), thereby providing an output light field to the projection device 5000 for projection.

Upstream of the optical path, the first and second light fields input to the beam modulation device 1000 can be provided by a polarization modulation device 2000 configured to modulate the polarization state of one but not the other of the third and fourth light fields to be output accordingly upon receiving the third and fourth light fields having substantially the same polarization state, and then to provide the first and second light fields, respectively, to the beam modulation device 1000. In one example shown in fig. 3, the third and fourth light fields input to the polarization modulation device 2000 are both S polarized, with the aid of the polarization modulation device 2000, the S polarized third light field is modulated into a P polarized first light field and the S polarized fourth light field into an S polarized second light field. Other embodiments are possible, but not shown, in which the third and fourth light fields input to the polarization modulation device 2000 are P-polarized, or the first and second light fields output are S-polarized and P-polarized, respectively. More specifically, the polarization modulation device 2000 can be configured to rotate the linear polarization axis of one of the third light field and the fourth light field by 90 °, and can optionally include a faraday rotator, a birefringent rotator, or a prismatic rotator. For example, the polarization modulation device 2000 can include a half-wave plate that is essentially a birefringent rotator.

Further upstream, the third and fourth light fields input to the polarization modulation device 2000 can be provided by a polarization device 3000 configured to polarize the unpolarized fifth and sixth light fields incident thereto for output accordingly, thereby providing the polarization modulation device 2000 with third and fourth light fields, respectively, having substantially the same polarization state. In a particular embodiment, the polarizing device includes a PCS polarizing array of front fly's eye lenses, rear fly's eye lenses, and prisms. The front fly-eye lens is configured to optically divide each of the fifth light field and the sixth light field into a plurality of light beams; the rear fly-eye lens is configured to focus a plurality of light beams on a rear surface thereof; the PCS polarization array of the prism is configured to polarize the focused plurality of light beams output from the posterior fly's eye lens to obtain a third light field and a fourth light field. Further details are provided below using specific example 1.

Further upstream, an unpolarized fifth light field and an unpolarized sixth light field input to the polarizing device 3000 are provided by the light source device 4000.

Each of the fifth and sixth light fields can comprise a single light beam, however, according to some preferred embodiments of the projection system, each of the fifth and sixth light fields, the third and fourth light fields, and the first and second light fields is a composite white light field formed by spatial coupling of two light fields of each pair, such that the projection system can be applied in a television projection system or VR/AR display system to project color images. For this purpose, in each pair of light fields of each composite white light field, one light field is configured as a time-division coupled light field comprising first and second primary light beams (i.e. the first and second primary light beams are time-division coupled to each other) and the other light field is configured as a third primary light beam. In the illustrative example of fig. 3, the fifth light field and the respective third and first light fields are each configured as a time-divided coupled light field (labeled in the figure) comprising first and second primary light beams coupled to each other in a time-divided manner. The sixth light field and the corresponding fourth and second light fields each comprise third primary light.

According to some embodiments, the first primary light can be blue light (B), the second primary light and the third primary light are green light (G) and red light (R) or red light (R) and green light (G), respectively.

According to these schemes described above, the light source device 4000 is configured to emit the first primary color light (i.e., blue light), and is further configured to obtain each of the second primary color light (i.e., green light) and the third primary color light (i.e., red light) by excitation of the corresponding fluorescent material (i.e., dye) by the first primary color light (i.e., blue light).

As shown in fig. 4A, in one specific embodiment, which will also be described in detail in embodiment 1 below, the light source apparatus 4000 includes a light source module 4100 including a first light source sub-module 4110 and a second light source sub-module 4120 configured to emit a first beam of first primary color light and a second beam of first primary color light (e.g., two beams of blue light), respectively. The light source device 4000 further comprises a first phosphor plate 4200 and a second phosphor plate 4300, which are optically aligned with the first and second beams of first primary light and are configured to receive the first and second beams of first primary light, respectively.

The first fluorescent sheet 4200 includes a transmissive region 4210 and a first fluorescent region 4220 on a surface thereof facing the first beam of first primary light. The first fluorescent region 4220 comprises a first fluorescent material (i.e., dye # 1) capable of generating a second primary color light when excited by the first primary color light. The first fluorescent patch 4200 is further configured to alternately face the transmissive region 4210 and the first fluorescent region 4220 in a predetermined manner (e.g., for a predetermined duration in one period) to the first beam of first primary color light such that when the transmitted first beam of first primary color light (i.e., the transmitted first primary color light) and the light beam of second primary color light generated in the first fluorescent region (i.e., the excited second primary color light, e.g., green light in fig. 4A) are spatially optically combined, e.g., by modulating the light paths of the transmitted first primary color light and the excited second primary color light, a time-division coupled light field is formed, thereby generating a fifth light field. The second fluorescent sheet 4300 contains a second fluorescent region 4320 including a second fluorescent material (i.e., dye # 2) on its surface facing the second beam of the first primary color light, the second fluorescent material being configured such that, when excited by the second beam of the first primary color light, a light beam of the third primary color light (e.g., excitation red light in fig. 4A) is generated from the second fluorescent region 4320, resulting in a sixth light field.

In this context, alternatively, the first phosphor sheet 4200 can be in the form of a rotating wheel (i.e. a color wheel) on which each of the transmissive region and the first phosphor region is arranged in a sector region. The angle of the transmissive region and the angle of the first fluorescent region can alternatively be configured complementary (i.e. 360 ° in total). For example, they can be about 89 ° -91 ° and about 269 ° -217 °, respectively, and preferably can be about 90 ° and about 270 °. Furthermore, the rotating wheel can have a rotational speed of at least 7200rpm in order to achieve an alternating acquisition of the first and second primary light for generating a time-divided coupled light field (i.e. a fifth light field). Alternatively, the second fluorescent sheet 4300 can also be in the form of a rotating wheel.

In order to achieve a spatial combination of the light paths of the transmitted first primary light and the excited second primary light, the light source device can further comprise a set of reflectors arranged such that the light paths of the first beam of first primary light transmitted through the transmission region are redirected to be optically combined with the light paths of the light beams of the second primary light, thereby generating a fifth light field.

In any embodiment of the light source device, each of the first and second light source sub-modules of the light source modules can comprise a laser diode array. The light source module can further include a first collimating lens array and a second collimating lens array disposed over the light emitting surfaces of the first light source sub-module and the second light source sub-module, respectively. The sub-eyes in each of the first and second collimating lens arrays are arranged to be aligned corresponding to the laser diodes in the laser diode array of the corresponding light source sub-module. Further, each sub-eye includes a hyperbolic aspherical lens whose curved surface is expressed as:

Here, C _x Is the curvature of the hyperbolic aspherical lens in the x direction, C _y Is the curvature of the hyperbolic aspherical lens in the y direction, K _x Is the cone coefficient K of the hyperbolic aspherical lens in the x direction _y Is the conic coefficient of the hyperbolic aspherical lens in the y direction.

The light source device can further include first and second dichroic filters disposed over the light emitting surfaces of the first and second light source sub-modules, respectively, and configured to filter each of the first and second beams of primary light, respectively.

The light source apparatus can also be configured such that the far field of the first primary light is gaussian distributed, such that the light source apparatus further comprises a first diffuser and a second diffuser, which are arranged between the first light source sub-module and the first dichroic filter and between the second light source sub-module and the second dichroic filter, respectively. The first and second diffusion sheets are configured to diffuse the first and second beams of first primary light such that their far fields are spread to have a bi-directional flat-top-like profile. Further, each of the first diffusion sheet and the second diffusion sheet can be optionally configured to have a two-way diffusion characteristic and have a diffusion half angle of about 1.2 ° to 1.8 ° in the horizontal direction and a diffusion half angle of about 0.65 ° to 1.05 ° in the pitch direction. In a preferred embodiment, the first diffusion sheet and the diffusion half angle of the first diffusion sheet can each be about 1.5 ° in the horizontal direction and about 0.85 ° in the pitch direction.

In order to eliminate as much as possible the speckle of the light field formed by the light of the first primary color, the light source device can further comprise one or more of the following means: (1) a transmissive region comprising a fan-shaped diffuser; (2) A collimating lens module disposed over the light emitting surface of the first fluorescent sheet; (3) A collimation compensating lens and a third diffusion sheet disposed on an optical path of the first beam of the first primary color light, the third diffusion sheet being configured to have a continuous small movement. More specifically, the third diffusion sheet can be mechanically coupled (i.e., connected) with a vibration motor configured to have a vibration frequency of 100Hz to 300Hz, and the third diffusion sheet can have a diffusion half angle of 2 ° to 3 °.

The light source apparatus can further include a first condensing lens module and a second condensing lens module disposed between the first dichroic filter and the first fluorescent sheet and between the second dichroic filter and the second fluorescent sheet, respectively. Each of the first and second condenser lens modules includes first and second condenser lens sub-modules including an aspherical lens and a spherical lens, respectively, in a light transmission direction. Alternatively, the aspherical surface of the aspherical lens can be expressed as:

Where c is the curvature at the sphere vertex, k is the quadratic aspherical coefficient, A _n And taking 2-7 as the aspherical coefficient of the higher-order term, wherein ρ is the normalized radial coordinate.

In the above embodiment, the first primary color light is blue light (B), and the second and third primary color lights are green light (G) and red light (R) or red light (R) and green light (G), respectively. Furthermore, the generation of the second and third primary light depends on the excitation of the respective dye material by the first primary light. It should be noted, however, that these configurations represent only illustrative examples and should not be construed as limiting the scope of the present disclosure. Other embodiments are also possible.

For example, in another embodiment shown in fig. 4B, the light source apparatus 4000 is configured to emit two beams of third primary light (e.g., a first beam of blue light and a second beam of blue light as shown in fig. 4B) by means of the first and second light source sub-modules 4110 and 4120, respectively. The third fluorescent sheet 4400 (e.g., a rotating color wheel) has a third fluorescent region 4410 (including dye # 1) and a fourth fluorescent region 4420 (including dye # 2) on a surface thereof facing the first beam of blue light, and is configured to alternately generate a beam of first primary color light (i.e., excited green light) and a beam of second primary color light (i.e., excited red light) when excited by the first beam of third primary color light (i.e., blue light). The light beams of the first primary color light and the light beams of the second primary color light alternately generated by the third fluorescent sheet 4400 can be managed to be coupled and output as a fifth light field of time-division coupling. The second light source sub-module 4120 directly provides the sixth light field with the second beam of the third primary color light (i.e., blue light). This embodiment of the light source apparatus 4000 has a relatively simple structure.

In yet another example, the light source device 4000 can be configured to emit (e.g. by means of a first light source sub-module) a first primary color light and to emit (e.g. by means of a second light source sub-module) a second primary color light, and further configured to obtain a third primary color light by excitation of the respective fluorescent material by the first primary color light or the second primary color light. In such a specific embodiment, the first, second and third primary lights are blue (B), green (G) and red (G), respectively, and the light source device is configured to emit blue and green light individually and is further configured to obtain red light by excitation of the respective fluorescent materials by the emitted green light. Thus, the fifth light field output comprises blue and green light coupled in time, and the sixth light field output comprises red light.

Hereinafter, a specific embodiment of a laser television projection system (i.e., embodiment 1) is provided as an illustrative example.

Fig. 5 and 6 illustrate front and bottom views, respectively, of a laser television projection system shown in a schematic diagram according to one particular embodiment of the present disclosure.

As shown, this particular embodiment of a laser television projection system includes: the device comprises a projection light source module 1, a homogenizing and polarizing module 2, a half-wave plate 5, a PBS prism 6, an LCOS light valve component 8 and a projection lens 9.

The projection light source module 1 is configured to provide a first white light field. The first white light field is essentially a coupled light field comprising first, second and third primary light. It is further configured such that the first primary light is time-coupled with the second primary light to first obtain a time-coupled light field, and the time-coupled light field is further spatially coupled with the third primary light to obtain a first white light field.

The homogenizing and polarizing module 2 is configured to polarize the first white light field, resulting in a second white light field. In the second white light field, each light is a preset type of polarized light, and the preset type of polarized light is one of P-polarized light and S-polarized light.

The half-wave plate 5 is configured to phase-convert one of the time-division coupled light field or the third primary light field in the second white light field, resulting in a third white light field. The third white light field includes P-polarized light and S-polarized light.

The PBS prism 6 is configured to transmit P-polarized light in the third white light field and reflect S-polarized light in the third white light field. The first reflected light field obtained by the first LCOS light valve after the P polarized light is transmitted and the second reflected light field obtained by the second LCOS light valve after the S polarized light is reflected are transmitted through the PBS prism 6 and then are emitted into the projection lens 9.

The LCOS light valve assembly 8 includes a first LCOS light valve and a second LCOS light valve.

In the particular laser television projection system shown in fig. 5 and 6, the polarization direction of the time-division coupled light field in the third white light field and the polarization direction of the third primary color light field are arranged to differ by 90 ° by means of a combination of homogenization and polarization module 2 and half-wave plate 5. Furthermore, the time-division coupled light field and the third primary color light are transmitted to their corresponding light valves (i.e., the first and second LCOS light valves) in the LCOS light valve assembly 8, respectively, via the PBS prism 6. In this way, the problem of using too many lens elements due to spectral folding of the relay light path and other factors in a laser television projection system having a conventional three-plate light valve structure can be avoided. The reduced use of lens elements can shorten the rear intercept of the projection lens 9 and effectively reduce the thickness of existing laser television projection systems, thereby reducing overall profile and cost. Display brightness and picture quality can be improved by using a dual LCOS light valve architecture, thereby meeting the requirements of high resolution and ultra-short focal projection.

In this particular embodiment of a laser television projection system, projection lens 9 employs a UST projection lens, and more particularly a 4K high resolution ultra-short focal projection lens. The projection lens 9 comprises a positive focal power lens group, a negative focal power lens group and a reflecting bowl. The projection lens 9 adopts a refractive-reflective object space telecentric design, the transmittance of the projection lens 9 is less than 0.25, the projection size of the projection lens 9 is 80-120 inches, and the equivalent rear intercept of the projection lens 9 in air is more than 15.2mm. It should be noted that other types of projection lenses can also be used according to different embodiments of the present disclosure.

Referring to fig. 5 and 6, fig. 5 is a front view of a laser television projection system provided by some embodiments of the present disclosure, and fig. 6 is a bottom view of the laser television projection system provided by some embodiments of the present disclosure. The laser television projection system includes: the device comprises a projection light source module 1, a homogenizing and polarizing module 2, a half-wave plate 5, a PBS prism 6, an LCOS light valve component 8 and a projection lens 9. The LCOS light valve assembly 8 includes a first LCOS light valve and a second LCOS light valve;

the projection light source module 1 is configured to provide a first white light field, and the first white light field is a coupled light field comprising first, second and third primary light. The first primary light is time-coupled with the second primary light to obtain a time-coupled light field, and the time-coupled light field is spatially coupled with the third primary light to obtain a first white light field.

The homogenizing and polarizing module 2 is configured to polarize the first white light field to obtain a second white light field. In the second white light field, each light is a preset type of polarized light, and the preset type of polarized light is one of P-polarized light and S-polarized light.

The half-wave plate 5 is configured to phase-convert one of the time-division coupled light field or the third primary light field in the second white light field to obtain a third white light field. The third white light field includes P-polarized light and S-polarized light.

The PBS prism 6 is configured to transmit P-polarized light in the third white light field and reflect S-polarized light in the third white light field. The first reflected light field obtained by the first LCOS light valve after the P polarized light is transmitted and the second reflected light field obtained by the second LCOS light valve after the S polarized light is reflected are transmitted through the PBS prism 6 and then are incident on the projection lens 9.

In the laser television projection system shown in fig. 5 and 6, the polarization direction of the time-division coupled light field in the third white light field and the polarization direction of the third primary color light field will differ by 90 ° by the combination of homogenization and polarization module 2 and half-wave plate 5. Furthermore, the light field and the light of the third primary color are time-division coupled by the PBS prism 6 to be transmitted to the corresponding light valve. In this way, the use of excessive lens elements due to spectral folding of the relay light path and other factors in a three-piece light valve structure can be avoided. The reduced use of lens elements can shorten the rear intercept of the projection lens 9 and effectively reduce the thickness of the existing laser television projection system, thereby reducing the overall profile and cost. Display brightness and picture quality can be improved by using a dual LCOS light valve architecture, thereby meeting the requirements of high resolution and ultra-short focal projection.

Furthermore, in one embodiment of the present disclosure, the projection lens 9 can employ a UST projection lens, more specifically a 4K high resolution ultra short focal projection lens. The projection lens 9 comprises a positive focal power lens group, a negative focal power lens group and a reflecting bowl. The projection lens 9 adopts a refractive-reflective object space telecentric design, the transmittance of the projection lens 9 is less than 0.25, the projection size of the projection lens 9 is 80-120 inches, and the equivalent rear intercept of the projection lens 9 in air is more than 15.2mm.

In other embodiments, other types of projection lenses can be used. There is no limitation in this context.

In addition, a 1/4 wave plate 7 can be arranged between the LCOS light valve component 8 and the PBS prism 6, which can improve the contrast of the picture.

Specifically, a first 1/4 wave plate can be disposed between the first LCOS light valve and the PBS prism 6, and a second 1/4 wave plate can be disposed between the second LCOS light valve and the PBS prism 6.

In particular, H-ZLAF52A material can be used for PBS prism 6, which allows the polarization contrast ratio of PBS prism 6 to be greater than 1000:1, so as to promote the picture contrast.

Specifically, the PBS prism 6 can be formed by gluing two triangular prisms. The glued surface of each triangular prism is plated with a polarization beam splitting film. The S-polarized light is reflected at the polarization splitting film, and the P-polarized light is transmitted through the polarization splitting film.

Further, referring to fig. 7, fig. 7 shows a right side view of a partial structure (assembly structure of the PBS prism 6 and the LCOS light valve assembly 8) in the embodiment of the laser television projection system shown in fig. 6. One of the first and second LCOS light valves is disposed over the top of the PBS prism 6, and the other is disposed over the side of the PBS prism 6.

The projection lens 9, the PBS prism 6, and the second LCOS light valve are disposed in the same linear direction, and the PBS prism 6 is disposed between the projection lens 9 and the second LCOS light valve.

In particular, the first and second LCOS light valves can have dimensions of approximately 0.55 inches, enabling the size of the laser television projection system to be reduced.

Specifically, the P-polarized light in the third white light field is transmitted through the polarization splitting film of the PBS prism 6, and then reflected back through the first LCOS light valve, thereby obtaining a first reflected light field. The first reflected light field is S polarized light. The first reflected light field is reflected at the polarizing beam-splitting film of the PBS prism 6 and then transmitted to the projection lens 9. The S-polarized light in the third white light field is transmitted to the polarization splitting film of the PBS prism 6. The second reflected light field is P polarized light, and the second reflected light field is transmitted through the polarization splitting film of the PBS prism 6, and then transmitted to the projection lens 9.

Further, the first primary color light is blue light, the second primary color light is green light, and the third primary color light is red light. Alternatively, the first primary color light is blue light, the second primary color light is red light, and the third primary color light is green light.

Further, the half-wave plate 5 can be an R (red) half-wave plate, an RB (red blue) half-wave plate, a G (green) half-wave plate or a GB (green blue) half-wave plate.

The R half-wave plate is configured to rotate the polarization direction of the red light by 90 °; the RB half-wave plate is configured to rotate the polarization directions of red and blue light by 90 °; the G half-wave plate is configured to rotate the polarization direction of the green light by 90 °; the GB half-wave plate is configured to rotate the polarization direction of the green and blue light by 90 °.

Specifically, if the first primary color light, the second primary color light, and the third primary color light are blue light, green light, and red light, respectively, the half-wave plate 5 can be an R half-wave plate or a GB half-wave plate, as long as the polarization directions of the time-division coupled light field and the third primary color light in the third white light field differ by 90 °. If the first, second and third primary lights are blue, red and green light, respectively, the half-wave plate 5 can be a G half-wave plate or an RB half-wave plate, as long as the polarization directions of the time-division coupled light field and the third primary light in the third white light field differ by 90 °.

The homogenizing and polarizing module 2 comprises a front fly's eye lens, a rear fly's eye lens and a PCS polarizing array prism. The first white light field is split into a plurality of light arrays after passing through the anterior fly-eye lens, and the light arrays are focused on the rear surface of the posterior fly-eye lens. The PCS polarization array prism polarizes the light field transmitted through the rear fly eye lens, thereby obtaining a second white light field.

Specifically, referring to fig. 8, fig. 8 shows a block diagram of a PCS polarization array prism provided in an embodiment of the disclosure. The PCS polarization array prism includes a first parallel square prism 201, a second parallel square prism 202, a metal plate 203, and a half-wave plate 204. The number of the first parallel square prism 201, the second parallel square prism 202, the metal plate 203, and the half-wave plate 204 is more than one. The first and second parallel

tetragonal prisms

201 and 202 and … … are arranged from bottom to top. Both ends of each of the first and second parallel

tetragonal prisms

201 and 202 are vertical planes. A polarization splitting film is disposed between each first parallel square prism 201 and its adjacent second parallel square prism 202. Metal sheets 203 are provided at the front end of each first parallel square prism 201 in a one-to-one correspondence. The light field transmitted through the rear fly's eye lens passes through the space between every two adjacent metal sheets 203 into the second parallel tetragonal prism 202.

When the half-wave plate 204 is disposed at the rear end of the first parallel square prism 201 and the half-wave plate 204 corresponds to the first parallel square prism 201 one by one, the S-polarized light in the first white light field is reflected by the polarization splitting film, then vertically directed to the adjacent polarization splitting film, reflected there, and then horizontally directed to the rear end of the second parallel square prism 202; while the P-polarized light in the first white light field is transmitted through the polarization splitting film and then is incident at the rear end of the first collimating square 201, and the polarization direction of the P-polarized light is rotated by 90 ° while passing through the half-wave plate 204. Thus, the light included in the second white light field is S polarized light.

When the half-wave plate 204 is disposed at the rear end of the second parallel square prism 202 and the half-wave plate 204 corresponds one-to-one with the second parallel square prism 202, the P-polarized light in the first white light field is transmitted through the polarization splitting film and then emitted at the rear end of the first parallel square prism 201; and the S polarized light in the first white light field is reflected by the polarized light splitting film, and then vertically irradiates to the adjacent polarized light splitting film and is reflected. When the S-polarized light is transmitted horizontally through half-wave plate 204, the polarization direction is rotated by 90 °. Thus, the light comprised in the second white light field is P polarized light.

A shaping lens module 3 and a folding reflector 4 are arranged between the homogenizing and polarizing module 2 and the half-wave plate 5.

The shaping lens module 3 includes a first lens and a second lens. After the second white light field transmitted through the homogenizing and polarizing module 2 passes through the first lens, the second white light field is reflected by the folding mirror 4 to the second lens and then passes through the second lens to the half-wave plate 5;

the shaping lens module 3, the front fly's eye lens and the rear fly's eye lens are arranged in a manner required to form a kohler illumination system so that a uniform illumination light field is formed at the exit pupil position of the shaping lens module.

In the laser television projection system provided by the embodiment of the present disclosure, the first white light field is divided into a plurality of light arrays after passing through the front fly-eye lens, and then focused on the rear surface of the rear fly-eye lens, and then passes through the space between the adjacent metal sheets 203. In this way, the utilization rate of the first white light field can be ensured, and the loss of the second white light field at the PCS polarization array prism can be reduced. In addition, the horizontal position of each half-wave plate 204 coincides with the horizontal position of the space between the adjacent metal plates 203, which can better improve the utilization rate of the first white light field and further reduce the loss of the second white light field at the PCS polarization array prism.

In addition, in another embodiment of the present disclosure shown in fig. 9, a block diagram of a projection light source module according to an embodiment of the present disclosure is shown. The projection light source module 1 includes: a light source module 101, a first dichroic filter 103, a second dichroic filter 104, a first fluorescent wheel 106 (i.e. a first color wheel), a second fluorescent wheel 107 (i.e. a second color wheel), a first reflector 109, a second reflector 110, and a third reflector 111.

The light source module 101 is configured to emit two parallel first primary colors of light, one of which is directed to the first fluorescent wheel 106 and the other of which is directed to the second fluorescent wheel 107.

The first fluorescent wheel 106 includes a transmissive region, a first fluorescent region, and a heat dissipation substrate corresponding to the first fluorescent region. The heat dissipation substrate is coated with a specular high-reflection film (or a specular high-reflection surface, etc.) on one side close to the first fluorescent region. The first primary color light passes through the second dichroic filter 104 disposed between the light source module 101 and the first fluorescent wheel 106, and then is directed to the first fluorescent wheel 106. The first primary light is excited when it impinges on the first fluorescent region, resulting in second primary light. The second primary light is reflected by the specular highly reflective film and then impinges on and is reflected by the second dichroic filter 104 to obtain a horizontal light field of the second primary light. When the first primary color light impinges on the transmission region, it passes through the transmission region, and the first primary color light transmitted through the transmission region is reflected by the first reflector 109, the second reflector 110, and the third reflector 111 in order to obtain a horizontal light field of the first primary color light.

The horizontal light field of the first primary light is coupled with the horizontal light field of the second primary light in a time-sharing manner after passing through the second dichroic filter 104, thereby obtaining a time-sharing coupled light field.

The second fluorescent wheel 107 includes a second fluorescent region and a heat dissipation substrate corresponding to the second fluorescent region. The side of the heat dissipation substrate near the second fluorescent region is coated with a specular high-reflection film (or a specular high-reflection surface, etc.). The first primary color light passes through the first dichroic filter 103 disposed between the light source module 101 and the second fluorescent wheel 107, and then is emitted onto the second fluorescent region of the second fluorescent wheel 107 to be excited, thereby obtaining third primary color light. The third primary light is reflected by the specular high reflection film, and then is incident on and reflected by the first dichroic filter 103, so that a horizontal light field of the third primary light is obtained.

Specifically, the first fluorescent wheel 106 is provided with a motor and a controller that controls the motor to maintain the rotation speed of the first fluorescent wheel 106 at 7200rpm or 14400rpm; the second fluorescent wheel 107 is also provided with a motor and a controller that controls the motor to maintain the rotation speed of the second fluorescent wheel 107 at 7200rpm or 14400rpm.

In addition, the light source module 101 includes a first array laser light source sub-module and a second array laser light source sub-module, and the first array laser light source sub-module and the second array laser light source sub-module have the same structure.

Each of the first array laser light source sub-module and the second array laser light source sub-module includes a laser diode array, a thermally conductive copper plate, a thermally conductive tube, a heat sink, a collimating lens array, a power supply, a control system, and a fan.

The laser diode arrays are uniformly arranged on the heat-conducting copper plate. The heat conducting pipe is inserted into the heat conducting copper plate. The heat conduction pipe contains a refrigerant, and the other end of the heat conduction pipe is connected with the radiating fin. And the heat of the radiating fins is taken away under the action of a fan. The power supply is a constant current power supply. The control system controls the magnitude of the current using a PWM (pulse width modulation ) mode, controls the on-off state and intensity of the current in the laser diode array, and monitors the temperature of each target bar of the laser diode array and the rotational speed of the fan. The collimating lens array is arranged at the front end of the laser diode array, and sub-eyes on the lens surface of the collimating lens array are arranged in one-to-one correspondence with the laser diodes in the laser diode array.

Each sub-eye on the lens surface of the collimating lens array adopts a hyperbolic aspherical lens, and the hyperbolic equation of the curved surface of the hyperbolic aspherical lens is expressed as:

here: c _x Is the curvature of the hyperbolic aspherical lens in the x direction, c _y Is the curvature of the hyperbolic aspherical lens in the y direction, k _x Is the conic coefficient k of hyperbolic aspheric lens in x direction _y Is double in numberConic coefficient of curved aspherical lens in y direction.

By adopting the sub-eye structure, the laser field can be well collimated, and the beam divergence angle can be reduced.

In addition, the far field of the first primary color light is Gaussian;

the diffusion sheet 102 is disposed between the light source module 101 and the first dichroic filter 103 or the second dichroic filter 104, and the diffusion sheet 102 includes a first diffusion sheet and a second diffusion sheet.

Correspondingly, a first diffuser is arranged between the first array light source module and the second dichroic filter 104, and a second diffuser is arranged between the second array light source module and the first dichroic filter 103;

the first and second diffusion sheets are configured to diffuse the first primary light such that the far field of the first primary light can be expanded to have a bi-directional flat-top-like profile.

Specifically, the first diffusion sheet is configured to reflect light of the second primary color in the excitation-return light field (excitation-return light field), and is also configured to filter light other than the light of the second primary color in the excitation-return light field. The second diffuser is configured to reflect light of the third primary color in the excitation-return light field and is also configured to filter light other than the light of the third primary color in the excitation-return light field. Thus, the white field color matching requirement can be met.

Specifically, if the first fluorescent region on the first fluorescent wheel 106 is provided with a green fluorescent sheet, only light having a wavelength greater than 500nm remains in the light field reflected via the second dichroic filter 104. If the second fluorescent region on the second fluorescent wheel 107 is provided with red fluorescent sheets, only light having a wavelength of more than 600nm remains in the light field reflected by the first dichroic filter 103.

The first diffusion sheet and the second diffusion sheet are configured to each have a dichroic diffusion characteristic in which a diffusion half angle is controlled to be 1.2 ° to 1.8 ° in a horizontal direction and 0.65 ° to 1.05 ° in a pitch direction. Preferably, the half angle of diffusion is about 1.5 ° in the horizontal direction and about 0.85 ° in the pitch direction.

In addition, a condensing lens module 105 is included in the system, which includes a first condensing lens sub-module and a second condensing lens sub-module;

the first condenser lens sub-module is disposed between the first dichroic filter 103 and the second fluorescent wheel 107. The first condenser lens sub-assembly is configured to focus the first primary light transmitted through the first dichroic filter 103 on the second fluorescent wheel 107, thereby forming a stripe-shaped spot, and collimate the third primary light excited by the second fluorescent wheel 107 into a parallel light field, which is then directed to the first dichroic filter 103;

The second dichroic mirror sub-module is disposed between the second dichroic filter 104 and the first fluorescent wheel 106. The second dichroic mirror sub-module is configured to focus the first primary light transmitted through the second dichroic filter 104 onto the first fluorescent wheel 106, thereby forming a stripe-shaped light spot, and to collimate the second primary light excited by the first fluorescent wheel 106 into a parallel light field, which is then directed towards the second dichroic filter 104.

In addition, the first condenser lens sub-module and the second condenser lens sub-module are substantially identical in structure. Each of the first and second condenser lens sub-modules includes an aspherical lens and a spherical lens. The aspheric lens is disposed closer to the light source module, and the spherical lens is disposed closer to the first fluorescent wheel or the second fluorescent wheel.

The equation for the aspherical surface of an aspherical lens can be expressed as:

Using the condensing lens module 105 described above, aberrations can be reduced, resulting in a better focusing effect, which facilitates focusing on the first and second

fluorescent wheels

106 and 107 to form a stripe-shaped spot. The combined focal length f of the first condenser lens sub-module and the second condenser lens sub-module is controlled to be 15mm to 20mm, and the maximum caliber is controlled to be within 32 mm.

In addition, the transmissive region can be provided with a fan-shaped diffuser, and the collimating lens module 108 is disposed between the first fluorescent wheel and the first reflector, which can eliminate speckle of the blue light field.

Specifically, the half angle of diffusion of the sector diffusion sheet is controlled to be 3.5 ° to 6.5 °.

A collimation compensation lens 112 and a third diffusion sheet 113 are arranged in this order between the third reflector 111 and the second dichroic filter 104. The third diffusion sheet 113 is configured to move circularly left and right or up and down. Specifically, by loading the vibration motor on the third diffusion sheet 113, the third diffusion sheet 113 can be slightly translated left and right or up and down, and the motor vibration frequency is controlled to be 100Hz to 300Hz, which can eliminate the speckle of the blue light field.

Specifically, the diffusion half angle of the third diffusion sheet 113 is controlled to be 2 ° to 3 °. Preferably, the diffusion half angle of the third diffusion sheet 113 is about 2.5 °.

Further, the transmissive region is configured to have a sector structure (sector structure), and the first fluorescent region is configured to have a sector annulus structure. The angle of the transmissive region is 89 ° -91 °, and the angle of the first fluorescent region is 269 ° -271 °. The angle of the transmissive region is configured to be complementary to the angle of the first fluorescent region, which facilitates realization of a white light color matching field. When the angle of the transmission area is 90 degrees and the angle of the first fluorescent area is 270 degrees, the light distribution requirement can be well met.

The projection light source module of the laser television projection system provided by the embodiment of the disclosure realizes time-sharing coupling of the first primary color light and the second primary color light so as to obtain a time-sharing coupled light field, and also realizes space coupling of the time-sharing coupled light field and the third primary color light so as to obtain a first white light field. In addition, the use of two-way fluorescent wheels to achieve RGB color matching can improve the display gamut and solve the problem of speckle in pure laser display, thereby reproducing the objective world in rich and bright colors. By simply folding the light path, the system layout is compact, the thickness of the existing laser television can be effectively reduced, the overall appearance is reduced, and the cost is reduced.

Claims

1. A light beam modulation device for modulating an input light field entering therein along a first axis to obtain an output light field exiting from the light beam modulation device along a second axis orthogonal to the first axis, wherein the input light field comprises a first light field and a second light field, wherein one of the first light field and the second light field has an S-polarization state, and the other of the first light field and the second light field has a P-polarization state, the light beam modulation device comprising:

A polarizing beam splitter, PBS, prism comprising two right angle prisms attached to each other on their respective base surfaces and arranged such that the first axis and the second axis are both substantially 45 ° with respect to an interface between the two right angle prisms, wherein the PBS prism is provided with an optical entrance surface allowing the input light field to enter therethrough and an optical exit surface allowing the output light field to exit therefrom, and an interface of the PBS prism is configured to selectively allow P-polarized incident light to be transmitted through the interface and S-polarized incident light to be reflected by the interface; and

a liquid crystal on silicon LCOS assembly comprising a first LCOS panel and a second LCOS panel, wherein:

the first LCOS panel is aligned over a first side surface of the PBS prism opposite the optical incidence surface such that light incident on the first LCOS panel is reflected back to the PBS prism along the first axis;

the second LCOS panel is aligned over a second side surface of the PBS prism opposite the optical exit surface such that light incident on the second LCOS panel is reflected back to the PBS prism along the second axis; and

Each of the first and second LCOS panels includes a plurality of pixels on a reflective surface thereof, wherein each of the plurality of pixels is configured to controllably turn on or off such that a polarization state of a light beam reflected by a portion of the reflective surface corresponding to the light beam is changed or remains unchanged.

2. The beam-modulating device of claim 1, wherein the input light field is a white light field optically coupled by three primary colors, wherein:

the first light field comprises two of the three primary colors of light coupled to each other in a time-shared manner; and

the second light field comprises the last of the three primary colors of light.

3. The beam modulating device of claim 1, wherein the PBS prism further comprises a polarizing means sandwiched between the base surfaces of the two right angle prisms, wherein the polarizing means comprises a polarizing beam splitting film or a wire grid.

4. A beam modulating device according to any of claims 1-3, further comprising a 1/4 wave plate, wherein:

the one 1/4 wave plate is sandwiched between a first side surface of the PBS prism and the first LCOS panel, or between a second side surface of the PBS prism and the second LCOS panel.

5. A beam modulating device according to any of claims 1-3, further comprising two 1/4 wave plates sandwiched between a first side surface of the PBS prism and the first LCOS panel, and a second side surface of the PBS prism and the second LCOS panel, respectively.

6. The beam modulating device of claim 5, wherein the extinction ratio of the transmitted light of the PBS prism beam is at least 500:1.

7. the beam modulation device of claim 6, wherein the extinction ratio is at least 1000:1.

8. the beam modulation device according to claim 6 or 7, wherein each of the two right angle prisms comprises an optical glass selected from N-SF1, H-ZF3, or H-ZLAF.

9. The light beam modulation device according to claim 6 or 7, wherein at least one of an optical entrance surface, an optical exit surface, a first side surface, or a second side surface of the PBS prism is coated with an anti-reflection film.

10. A projection system comprising a beam modulating device according to any of claims 1-9.

11. The projection system of claim 10, wherein the input light field is a white light field optically coupled by three primary colors, wherein:

the second light field comprises the last of the three primary colors of light.

12. The projection system of claim 10 or 11, further comprising a polarization modulation device, wherein the polarization modulation device is configured to, upon receiving a third light field and a fourth light field having substantially the same polarization state, modulate the polarization state of one of the third light field and the fourth light field but not the polarization state of the other to output the first light field and the second light field, respectively.

13. The projection system of claim 12, wherein the polarization modulation device is configured to rotate the linear polarization axis of one of the third and fourth light fields by 90 °.

14. The projection system of claim 12, wherein the polarization modulation device comprises a faraday rotator, a birefringent rotator, or a prismatic rotator.

15. The projection system of claim 14, wherein the polarization modulation device comprises a birefringent rotator.

16. The projection system of claim 15, wherein the birefringent rotator comprises a half-wave plate.

17. The projection system of any one of claims 13 to 15, further comprising a polarizing device configured to polarize unpolarized fifth and sixth light fields incident therein to output the third and fourth light fields, respectively.

18. The projection system of claim 17, wherein the polarizing device comprises:

a front fly-eye lens configured to optically divide each of the fifth light field and the sixth light field into a plurality of light beams;

a rear fly-eye lens configured to focus the plurality of light beams on a rear surface thereof; and

a PCS polarization array of prisms configured to polarize the focused plurality of light beams to obtain the third light field and the fourth light field.

19. The projection system of claim 17, further comprising a light source device configured to provide the fifth light field and the sixth light field.

20. The projection system of claim 19, wherein the fifth light field and the sixth light field are configured to collectively form a white light field, wherein:

the fifth light field is a time-division coupled light field comprising first and second primary light; and

The sixth light field comprises third primary light.

21. The projection system of claim 20, wherein:

the first primary color light is blue light; and is also provided with

The second primary color light and the third primary color light are green light and red light or red light and green light respectively.

22. The projection system of claim 20 or 21, wherein the light source device is configured to emit the first primary color light and is further configured to derive each of the second and third primary color light by excitation of the respective fluorescent material by the first primary color light.

23. The projection system of claim 20 or 21, wherein the light source device is configured to emit the first and second primary light and is further configured to derive the third primary light by excitation of the respective fluorescent material by the first or second primary light.

24. The projection system of claim 22, wherein the light source device comprises:

the light source module comprises a first light source sub-module and a second light source sub-module, wherein the first light source sub-module and the second light source sub-module are configured to emit a first beam of first primary color light and a second beam of first primary color light respectively; and

A first fluorescent sheet and a second fluorescent sheet optically aligned with the first and second beams of first primary color light, respectively, and configured to receive the first and second beams of first primary color light;

wherein:

the first fluorescent sheet comprising a transmissive region and a first fluorescent region on a surface thereof facing the first beam of first primary light, wherein the first fluorescent region comprises a first fluorescent material capable of generating the second primary light when excited by the first primary light, wherein the first fluorescent sheet is further configured to alternately align the transmissive region and the first fluorescent region with the first beam of first primary light in a predetermined manner such that light beams of the first beam of first primary light and the second primary light generated from the first fluorescent region transmitted through the transmissive region are coupled in a time-sharing manner to be output as the fifth light field; and

the second phosphor plate includes a second phosphor region including a second phosphor material on a surface thereof facing the second beam of first primary color light, the second phosphor material being configured such that, when excited by the second beam of first primary color light, a beam of third primary color light is generated from the second phosphor region to be output as the sixth light field.

25. The projection system of claim 24, wherein the first phosphor sheet is in the form of a rotating wheel, and each of the transmissive region and the first phosphor region is disposed in a sector area on the rotating wheel.

26. The projection system of claim 25, wherein the angle of the transmissive region and the angle of the first fluorescent region are complementary and are about 89 ° -91 ° and about 269 ° -217 °, respectively.

27. The projection system of claim 25, wherein the rotating wheel has a rotational speed of at least 7200 rpm.

28. The projection system of claim 24, wherein the second fluorescent sheet is in the form of a rotating wheel.

29. The projection system of claim 24, wherein the light source device further comprises a set of reflectors arranged such that the optical path of the first beam of first primary color light transmitted through the transmission region is redirected to optically combine with the optical path of the second beam of primary color light to produce the fifth light field.

30. The projection system of claim 24, wherein in the light source modules, each of the first and second light source sub-modules comprises an array of laser diodes.

31. The projection system of claim 30, wherein the light source module further comprises first and second collimating lens arrays disposed over the light emitting surfaces of the first and second light source sub-modules, respectively, wherein the sub-eyes in each of the first and second collimating lens arrays are disposed in corresponding alignment with the laser diodes in the laser diode arrays of the corresponding light source sub-modules.

32. The projection system of claim 31, wherein each sub-eye comprises a hyperbolic aspherical lens having a curved surface expressed as:

wherein c _x Is the curvature of the hyperbolic aspherical lens in the x direction, c _y Is the curvature of the hyperbolic aspherical lens in the y direction, k _x Is the conic coefficient k of hyperbolic aspheric lens in x direction _y Is the conic coefficient of the hyperbolic aspherical lens in the y direction.

33. The projection system of claim 31 or 32, the light source apparatus further comprising first and second dichroic filters disposed over light emitting surfaces of the first and second light source sub-modules, respectively, and configured to filter each of the first and second beams of primary light, respectively.

34. The projection system of claim 33, wherein the far field of the first primary light is gaussian, wherein the projection system further comprises a first diffuser and a second diffuser disposed between the first light source sub-module and the first dichroic filter and between the second light source sub-module and the second dichroic filter, respectively, wherein:

the first and second diffusion sheets are configured to diffuse the first and second beams of first primary light such that their far fields are spread to have a bi-directional flat-top-like profile.

35. The projection system of claim 34, wherein each of the first and second diffusion sheets is configured to have a dichroic diffusion characteristic and has a diffusion half angle of about 1.2 ° -1.8 ° in a horizontal direction and a diffusion half angle of about 0.65 ° -1.05 ° in a pitch direction.

36. The projection system of claim 35, wherein a half angle of diffusion of the first diffusion sheet is approximately 1.5 ° in the horizontal direction and approximately 0.85 ° in the pitch direction.

37. The projection system of claim 35, wherein a half angle of diffusion of the second diffusion sheet is approximately 1.5 ° in the horizontal direction and approximately 0.85 ° in the pitch direction.

38. The projection system of claim 29, the light source apparatus further comprising at least one means for eliminating speckle of a light field formed by the first primary light, wherein the at least one means comprises one or a combination of:

a transmissive region including a sector-shaped diffusion sheet;

a collimating lens module disposed above the light emitting surface of the first fluorescent sheet; and

a collimation compensating lens and a third diffusion sheet disposed on an optical path of the first beam of first primary color light, wherein the third diffusion sheet is configured to have a continuous small movement.

39. The projection system of claim 38, wherein the third diffuser is mechanically coupled to a vibration motor configured to have a vibration frequency of 100Hz to 300 Hz.

40. The projection system of claim 38, wherein the third diffuser has a half angle of diffusion of 2 ° to 3 °.

41. The projection system of claim 33, the light source apparatus further comprising a first condenser lens module and a second condenser lens module disposed between the first dichroic filter and the first fluorescent sheet and between the second dichroic filter and the second fluorescent sheet, respectively, wherein each of the first condenser lens module and the second condenser lens module comprises a first condenser lens module and a second condenser lens module in a light transmission direction, the first condenser lens module and the second condenser lens module comprising an aspherical lens and a spherical lens, respectively.

42. The projection system of claim 41, wherein the aspherical surface of the aspherical lens is represented as:

43. The projection system of claim 20, wherein the light source device is configured to emit the third primary color light and is further configured to derive each of the first and second primary color light by excitation of the respective fluorescent material by the third primary color light.

44. The projection system of claim 43, wherein the light source device comprises:

the light source module comprises a third light source sub-module and a fourth light source sub-module, and the third light source sub-module and the fourth light source sub-module are configured to emit a first beam of third primary color light and a second beam of third primary color light respectively; and

a third phosphor sheet optically aligned with the first beam of third primary color light and configured to receive the first beam of third primary color light;

wherein:

the third fluorescent sheet includes a third fluorescent region and a fourth fluorescent region on a surface thereof facing the first beam of first primary color light, wherein:

The third fluorescent region comprises a third fluorescent material capable of generating the first primary light when excited by the third primary light;

the fourth fluorescent region comprises a fourth fluorescent material capable of generating the second primary light when excited by the third primary light;

the third fluorescent sheet is further configured to alternately face the third fluorescent region and the fourth fluorescent region in a predetermined manner toward the first beam of third primary color light, so that the light beam of the first primary color light generated from the third fluorescent region and the light beam of the second primary color generated from the fourth fluorescent region are coupled in a time-sharing manner to be output as the fifth light field; and

the second beam of third primary light is output as the sixth light field.

45. The projection system of claim 44, wherein the third phosphor sheet is in the form of a rotating wheel, each of the third phosphor region and the fourth phosphor region being disposed in a sector area on the rotating wheel.

46. The projection system of claim 45, wherein the rotating wheel has a rotational speed of at least 7200 rpm.

47. The projection system of any of claims 43-46, wherein

The first primary color light and the second primary color light are respectively green light and red light or respectively red light and green light;

The third primary color light is blue light.